[einpoklum]

> domains where Rust ... [is] already being used

The point is that Rust usage is still quite limited. This is a bit like C++ and D, two decades back; or perhaps even Scala and Java. The analogy isn't perfect, but the point is you had a language with a lot of potential usability-domain overlap which addressed some or many pain points and failures of the older, more popular language - but the older language embraced some of the alternative ideas, adopted them in a more-or-less compatible way, and made it not-attractive-enough to switch. So the newer languages lost momentum, and at least in the case of D - stopped gaining users and eventually sank into oblivion.

> other safer languages ... won't rewrite back into C++.

I mostly agree. Except... that some safe languages, like Java, pay for safety with a lot of overhead. And Dennard scaling is over. So, over time, there is some pressure to replace Java, or maybe C# code with something closer-to-the-metal. But we'll see.

[pjmlp]

D suffered from lack of focus, and company sponsoring, hence why it hardly mattered to C++ folks.

The domains that Java and .NET took away from C++ aren't coming back to C++, even if now they feel the pressure to have AOT and value types with better low level coding primitives.

Additionally Java and .NET applications that get rewritten, most likely will be in one of those C++ wannabe successors, even if C++ is part of the equation by using GCC/LLVM backends.

[einpoklum]

The thing is, that the "C++ successor language" sometimes ends up being C++ itself, a decade or two later.

As an example, take this question from 2008:

"How do I tokenize a string in C++?" https://stackoverflow.com/q/53849/1593077

A very popular, straightforward, and traditional-style answer to this question, , given early on, was:

  vector<string> split(const char *str, char c = ' ') {
      std::vector<std::string> result;
  
      do {
          const char *begin = str;
          while(*str != c && *str) { str++; }
          result.push_back(std::string(begin, str));
      } while (0 != *str++);
      return result;
  }

but a recent answer is:

   auto results = str | ranges::views::tokenize(" ",1);

which is in lazy-evaluated functional style, and doesn't even directly utilize the fugly standard C++ string class. This example is of course a bit simplistic (since the main change exhibited here is in the standard library), but the point is that the language has demonstrasted strong abilities to reconfigure how users tend to write code. But - perhaps I'm giving it more credit than it's due any this won't comen to pass.